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GB1504062A - Loop current detector - Google Patents

Loop current detector

Info

Publication number
GB1504062A
GB1504062A GB822576A GB822576A GB1504062A GB 1504062 A GB1504062 A GB 1504062A GB 822576 A GB822576 A GB 822576A GB 822576 A GB822576 A GB 822576A GB 1504062 A GB1504062 A GB 1504062A
Authority
GB
United Kingdom
Prior art keywords
oscillator
transistors
hook
transistor
winding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB822576A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anaconda Co
Original Assignee
Anaconda Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anaconda Co filed Critical Anaconda Co
Priority to GB822576A priority Critical patent/GB1504062A/en
Publication of GB1504062A publication Critical patent/GB1504062A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/2272—Subscriber line supervision circuits, e.g. call detection circuits

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Interface Circuits In Exchanges (AREA)

Abstract

1504062 Automatic exchange systems ANACONDA CO 2 March 1976 08225/76 Heading H4K A loop detector comprises a saturable reactor T1, having a winding 13 connected via a resistor R1 to an oscillator 23, e.g. of frequency 20 kHz, and a switching circuit 27 comprising three transistors Q1-Q3, the arrangement being such that with the line 14, 15 unlooped the output of the oscillator 23 turns transistor Ql off and on to keep transistors Q2, Q3 non conducting, whereas with the line looped the reactor saturates and no A.C. voltage is produced across winding 13 by the oscillator thereby to hold transistor Ql non conducting to cause transistors Q2, Q3 to conduct. The two different voltage levels produced at output 29 in the two respective conditions are used as on-hook and off-hook indications respectively. During loop disconnect dialling pulses the time constant of the circuit comprising R5, R6 and C2 is sufficient to keep transistor Q3 conducting so as to maintain the off-hook indication.
GB822576A 1976-03-02 1976-03-02 Loop current detector Expired GB1504062A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB822576A GB1504062A (en) 1976-03-02 1976-03-02 Loop current detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB822576A GB1504062A (en) 1976-03-02 1976-03-02 Loop current detector

Publications (1)

Publication Number Publication Date
GB1504062A true GB1504062A (en) 1978-03-15

Family

ID=9848355

Family Applications (1)

Application Number Title Priority Date Filing Date
GB822576A Expired GB1504062A (en) 1976-03-02 1976-03-02 Loop current detector

Country Status (1)

Country Link
GB (1) GB1504062A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0020822A1 (en) * 1979-06-21 1981-01-07 Amper S.A. Current detector circuit
FR2460077A1 (en) * 1979-06-26 1981-01-16 Constr Telephoniques CURRENT DETECTION CIRCUIT
GB2146201A (en) * 1983-09-06 1985-04-11 Gen Electric Co Plc Loop detectors for telephone line circuits

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0020822A1 (en) * 1979-06-21 1981-01-07 Amper S.A. Current detector circuit
FR2460077A1 (en) * 1979-06-26 1981-01-16 Constr Telephoniques CURRENT DETECTION CIRCUIT
GB2146201A (en) * 1983-09-06 1985-04-11 Gen Electric Co Plc Loop detectors for telephone line circuits

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee